Olefin copolymers of sulfur dioxide or carbon monoxide often have certain desirable features, such as good thermal stability and good resistance to certain organic liquids, and high melting points which makes them useful as molding resins. Of special interest are the ethylene copolymers, which can be relatively easily made. These polymers are often made by contacting the monomers with a catalyst system which includes a specified type of transition metal compound. However, these transition metal compounds are often quite expensive.
Palladium (and other transition metal) containing catalysts are often used to copolymerize carbon monoxide and olefins, see for instance the review article E. Drent, et al., Chem. Rev., vol. 96, pp. 663-681 (1996), and also U.S. Pat. Nos. 5,554,777; 4,904,759; 4,778,876; and 4,818,810.
What are needed are improved methods of making such copolymers which do not have the deficiencies inherent in the prior art. Other objects and advantages of the present invention will become apparent to those skilled in the art upon reference to the detailed description which follows hereinafter.